In March Dr Carson appeared on Fox News, and told the show’s host, Sean Hannity: “My thoughts are that marriage is between a man and a woman. It’s a well-established, fundamental pillar of society and no group, be they gays, be they NAMBLA (North American Man/Boy Love Association), be they people who believe in bestiality–it doesn’t matter what they are–they don’t get to change the definition.”

The Associated Press reported that, in a letter written to the dean of the medical school, Carson said he did not want to become a distraction from the ceremony.

On Friday Mr Carson wrote a letter to the University apologising for the negative attention his comments had brought and expressing sadness at the pain caused by “poorly chosen words”.

The same day Dr Paul Rothman, the University Medical School’s dean, said Dr Carson had the right to express his opinion, but added: “We recognize that tension now exists in our community because hurtful, offensive language was used.”

The American Academy of Pediatrics (AAP), which is well-known, and the opinions of which are considered influential by many, went on to endorse full adoption and foster care rights for all parents, irrespective of sexual orientation.